 
   ;; FIXED in my Rhino fork
   (let [cx     (Context/enter)
+        _      (.setLanguageVersion cx 200)
         _      (.setOptimizationLevel cx -1)
         scope  (.initStandardObjects cx)
         source (slurp (io/resource "babel-core/browser.js"))]


  (try
    (let [cx     (Context/enter)
          _      (.setOptimizationLevel cx -1)
          scope  (.initStandardObjects cx)
          source (slurp (io/resource "babel-core/browser.js"))]

      "Object.prototype.toString.call(undefined)"
      "<cmd>" 1 nil))

  ;; undefined
  (let [cx     (Context/enter)
        _      (.setOptimizationLevel cx -1)
        scope  (.initStandardObjects cx)
